Process for the preparation of 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-3-indoleacetoxyacetic acid

Abstract

The invention relates to a process for preparing 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-3-indoleacetoxyacetic acid which comprises reacting an indolecarboxylic acid or its derivatives with a compound of the formula HO--CH 2 --CO--O--R 2 in the presence of an inert organic solvent in a temperature range from -10° C. to 80° C., so that the resulting product is essentially free from the dechlorinated bi-product. The product of the process of the invention is a known anti inflammatory agent.

We claim: 
     
       1. Process for the preparation of 1-(4-chlorobenzoyl)-5 -methoxy-2-methyl-3-indoleacetoxyacetic acid (I), characterised in that indolecarboxylic acid or its derivatives of the general formula II ##STR16## in which R 1  represents the radical ##STR17## --O--SO 2  --CH 3 , ##STR18## is reacted with compounds of the general formula III ##STR19## in which R 2  represents hydrogen or ammonium, in the presence of inert organic solvents in a temperature range from -10° C. to 80° C. 
     
     
       2. Process according to claim 1, characterised in that the reaction is undertaken in a temperature range from -5° C. to 20° C. 
     
     
       3. Process according to claim 1, characterised in that diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, methylene chloride, chloroform, dichloroethane, dimethylformamide, N-methylpyrrolidone, toluene, xylene, acetone or methyl ethyl ketone are employed as the inert organic solvents. 
     
     
       4. Process according to claim 1 characterised in that R 1  denotes ##STR20## 
     
     
       5. Process according to claim 1, characterised in that R 2  denotes ammonium.